Crowds were small, consisting mainly of elderly Cubans who fled the island years ago and typically spend the days sipping espresso-like “cafe Cubano” and sharing memories of their homeland.

Standing in rain with signs denouncing the 49-year Castro regime, they expressed guarded optimism about Mr. Castro’s decision to relinquish power, uncertain that reforms in Cuba would follow.

“I’m happy about an end to almost 50 years of repression under Fidel,” said Jose Plancia, 73, who left the island in 1968. “However, I don’t see any real change.

“Raul does not have the same power as Fidel,” he said, referring to Mr. Castro’s younger brother who now heads Cuba’s government.

News of the elder Mr. Castro’s decision to give up the presidency of the communist island in an upcoming selection process reached Cubans here in the wee hours of this morning when an announcement by Mr. Castro himself was posted on the online version of Cuba’s state-run newspaper Granma.

Cuban leaders are scheduled to meet Sunday in Havana to select the country’s new president from a group of leaders known as the Council of State. Experts and Cubans here in Miami widely suspect that Raul Castro will be named his brother’s successor.

“I will not aspire to nor accept I repeat, I will not aspire to nor accept the post of president of the Council of State and commander in chief,” read the letter from the 81-year-old Mr. Castro, who due to ill health handed over authority to Raul Castro in July 2006.

Since then, Fidel Castro has not appeared in public though he has published some 80 editorials and met with numerous world leaders, including close friend and regional ally Hugo Chavez. In photos, he often appears frail, usually sitting, and clad in a tracksuit in the red, white and blue colors of the Cuban flag.

Mr. Castro’s decision to not pursue another term in office has sparked widespread speculation as to the future of the island nation just 90 miles from the U.S. coast.

Veteran Cuba watchers like Javier Corrales, an assistant professor of political science at Amherst College, said the decision was not a “big surprise” considering Mr. Castro’s diminished presence since handing over the reins to Raul.

“Fidel’s decision to step down in 2006 was really just a rehearsed retirement to see how society [in Cuba] would react,” said Mr. Corrales. Much has remained the same in Cuba since Raul assumed authority, he noted, and he predicted little would change unless someone other than Raul is named the country’s new leader.

“If anyone other than Raul was named the next president, then that would be big news,” Mr. Corrales said.

Others see today’s announcement as a watershed moment in a Cuban political landscape that has changed very little change since Fidel Castro led the overthrow of the country’s dictator Fulgencio Batista in 1959.

“Fidel’s announcement is quite significant, as it marks the end of one era and marks the beginning of a new regime,” said Georgetown professor of government Eusebio Mujal-Leon.

Mr. Mujal-Leon suspects the successor to Fidel, be it Raul or another candidate, will not be able to sustain Cuba’s hard-line communist policies.

“Raul and others can’t rule like Fidel did,” he said, noting that the younger Mr. Castro and other potential leaders like Cuban National Assembly President Ricardo Alarcon lack the charisma of Fidel.

“Cuba’s next leader will have to better people’s lives by providing them with jobs and food,” said Mr. Mujal-Leon. “These are things a charismatic leader doesn’t have to worry about.”